Electric switch and contact structure therefor



.June l0, 1930.

c. n AlNswoRTH ELECTRIC SWITCH AND CONTACT STRUCTURE THEREFOR Filed Dec.27, 1921 z sheets'sheet l n Ik Jiffy. 6. jrwe/vof'. .30C/Lx D. WCW-.Jai

June l0, 1930. c. D. AlNswoRTH ELECTRIC SWITCH AND CONTACT STRUCTURETHEREFOR 2 Sheets-Sheet 2 Filed Deo. 27, 1927 #111m j' .M 3o

Invelof".

Patented June '10, 1930 UNITED y ,s'rxrufs nPATEN'I- OFFICE CHESTER D.AINSWORTH, OF WOLLASTON, MASSACHUSETTS, ASSIGNOR TO CONDIT ELEC- TRICALMANUFACTURING CORPORATION, 0F SOUTH BOSTON, MASSACHUSETTS, A

CORPORATION 0F MASSACHUSETTS ELECTRIC SWITCH AND CONTACT STRUCTURETHEREFOR f Application led December 27, 1927. Serial No. 242,666.

This invention relates to electric switches and contact structurestherefor.

In the usual electric switch, consisting of a pair of vertical insulatedstuds adapted to be connected at the bottom by a vertically movablebridging member, the magnetic flux surrounding the studs and bridgingmember, when the switch is traverse by heavy current, tends toforceapart the cooperating contact members of both or at least tends( toreduce the contact pressure therebetween and thus to cause heatin andburning of the contacts. It is an ob]ect of this inven-l tion to providean arrangement of contact members and associated conducting componentsby which the conducting coin-r ponents are caused to react magneticallyand to apply a force on the contact members tol urge them together whenthe switch is traversed by a heavy current, thusto oppose the oppositelyacting ma netic reactions of the current in the genera yswitch circuiton the contact members.

A further object of the invention is the.

provision of a movably supported contact member and conducting meansassociated therewith arranged to set up magnetic forces acting on thecontact member in a direction to urge it against its cooperating contactmember. U

A further object of the invention is the provision of a movablysupported contact member and a conducting component forming aconductin,"y loop of which saidcontact member is a part, the magneticforces in the loop reacting on the contact member \to urge it inacircuit closing direction. n

A further object is generally to improve the construction and operationof electric switches.

Fig. 1 is a side elevation of the contact structure of an electricswitch embodying the invention.

Fig. 2 is an end view of the Structure of Fig.` 1. A

Fig.' 3 is a section along line 3-3 of Fig. 1.

Fig'. Lis a vertical sectional detail through gne of the movablysupported arcing memers.

vFig. 5 is a pers ective view of the conducting support o the arcingmembers.

Fig. 6 is a perspective sectional detail i1- lustrating the manner ofpivotally securing a contact member to the conductin support.

Fig. 7 is a perspective view cfg the supporting'bracket' for theconducting support.

Fig. 8 is a view similar to Fig. 4 and shows therelative directions ofthe current in the parts. l

Fig. 9 is a vertical elevation of a modified arrangement of contactmembers embodying` this invention.

ig. 10 is a view similar to Fig. 4 but illustrating the modified form ofcontact member.

The switch here shown includes a pair of vertical conducting rods orstuds 10 supported in insulators 12. The studs at the1r lower end eachcarry brushes 14 made up of a series of superim osed laminations theShanks of each of w ich is surrounded bya metal jacket 16. The stud ispassed through the shank and has lnuts 18 and 2O screw threaded thereonwhich serve to clamp the brush Xedly to the stud. The lower nut 18 has afiat bottom contact face vand comprises a.,stationary arcing member ofthe switch. `The movable switch member includes a bridging member 22whichxcomprises a conducting member of channel shape having atop flatcontact face 23 and depending webs 24 and is adapted tol be .on thelower end oan insulated liftingv or switchL rod 2 6. An invertedchannelsup' porting frame 27 having the at top wall 28 and the dependinglegs 30 is clamped to the screw threaded lower end 32 of the lifting rodunder said loosely supported bridging member 22 and between itsdepending webs 24 thereof and hasplaterally-extended struck-out tabs 34which are adapted to lie close to the inner faces of said depending websto hold said bridging member from undue lateral or angular displacementon the lifting rod. A rigid conducting support 36 is disposed withinsaid channel supporting frame 27 and comprises a flat bar which isreceived against the under face of the top wall 28 of the supportingframe and is secured thereto by screws 38. Said bar is extendedoutwardly in both directions beyond said frame and has downwardlyextended end sections 40 and inwardly directed lower sections 42 whichare parallel with and are spaced below the top section and has upwardlyextended end sections 44 which are terminated beneath and out of contactwith the horizontal top section. The end sections 40 have vertical slotsor openings 46 therein. The vertical rear sections have notches 48therein which provide upstanding projections 50 at the sides of thenotches. The auxiliary contact members each comprise a stiff bar 52 ofconducting vmaterial having an.upturned outer end 54 to which an arcingmember 56 is secured detachably by means of a bolt 58; and said arcingmember is arranged to bear against the under face of the stationaryarcing member or nut 18 when the switch is closed. The rear or innersection or shank 53 of the bar 52 is extended through one of theopenings 46 in the conducting support 36 and has opposed notches 60 inits side edges at its inner end which' are received loosely in theupstanding projections 50 of the vertical and inner end 44 of theconducting support \with the end of the shank lyin loosely in the notch48. A thin plate 62 as a notch 64 in its lower face in which the shankis received and said plate is secured to said upstanding projections 50by screws 65 whereby to secure the contact member in pivotal engagementwith the inner'section 44 of the conducting support againstv acciportionextended through the opening 46.

of the conducting support and thus serves sulating sleeve and serves tourge the contactl member upwardly. vWhen the switch is closed the"spring is adapted to be compressed as shown in Fig. 1 and the contactmember is adapted to float upon the spring.

The arrangement of the conducting support 36 and the contact memberforms a conducting loop which causes the movable Contact member to beforced against the cooperating stationary contact member -in dependentlyof the spring 74'when current flows through the auxiliary currentconducting path. Fig. 8 illustrates the instantaneous direction of thecurrent through the auxiliary current-conducting structure wherein thecurrent is in the direction of the arrow a, inwardly or from the Contactmember through the shank thereof to the inner end of the bottomhorizontal section 42 and in the opposite direction in said sectionoutwardly toward the vertical section 40 and upwardly through saidvertical section to the end of the top section 36 and inwardly towardthe left in said section as indicated by the arrow d to the similarcontactme1nber on the other side thereof. As

`the same direction in the shank 53 and in `the upper horizontal section36 and thereaction therebetween thus tends to draw the contact memberupwardly so that both the upper and lower sections 36 and 42respectively act on said contact member in a direction to force itupwardly and against the cooperating stationary contact or arcing member18. Since the sections 36 and 42 are close to the contact member theirmagnetic reactions on the contact member can be made great enough tooffset the oppositely-directed reaction between the contact. member andthe studs. A,

A pin 82 is extended through the webs 30 of the supporting frame 27 andlies within and close to the angle between each lower horizontal section42 and the inner upstanding end 44 of the conducting support and isinsulated therefrom by the insulating sleeve 84 and the washers 86 Fig.2 and serves to support the lower horizontal section against upwarddisplacement due to the" fulcruming of the contact member on the spring74 when the switch is in closed position and also to prevent the lowerhorizontal section from being displaced in a downward direction by themagnetic reac tion of abnormal currents. Said section, if displaceddownwardl brings the shank 53 of the contact mem r against theinsulating sleeve of said pin 82 and thus forces the arcing member 56thereof with increased effect upwardly against the cooperatingstationary arcing member.

In the modification shown in Fig. 9, the movable contact member 87 isvertically disposed and has it upper end in contact with the dependingstationary arcin member 88 and has its lower end 90 pivota ly connectedwith avertically extended rigid conducting member 92 and electricallyconnected therewith by a loop of flexible braid 94. The contact member87 and the conductor 92 cooperate to form the legs of a U-shapedconducting path, the current in the legs being in opposite directions,so that the contact member 87 is forced outwardly into pressure contactwith its arcing member 88 with a force greater than that resulting fromthe compression spring 96 alone. In this modificatlon, the magneticreaction of the current in the switch studs complements the magneticreaction in the U-shaped conducting path.

The modification shown in Fig. 10 is similar to that shown in Figs. 1through 6,

with the exception that the arcing member 56a carried by the shank 52aextends freely through a hole 98 in the upper horizontal section 36a ofthe conductin support for engagement with the cooperatlng stationarycontact 18. In this case, the opening 98 is the equivalent of theopening 46 of the previous figures. The current reactions in themodification shown in Fig. 10 are the samey as described in connectionwith Fig. 8.

I claim:

1.- In anelectric switch, the combination of fixed switch terminalshaving contact members at their ends, movable contact memberscooperating with said fixed contact members so arranged `that thecurrent traversing the general switch circuit tends to separate Saidcontact members, and relatively movable conducting elements included insaid switch circuit which `react independently and in op osition to thegeneral switch circuit to hold) said contact members together. 4

2. In an electric switch, a contact member. a cooperating movablecontact member, and a looped conducting member connected with saidmovable contact member and having relative movable parts disposed inposition to react magnetically in a direction to urge said contactmembers together.

3. In an electric switch, a contact member, a cooperatin movable contactmember having an exten ed current-carrying arm., and a conductorconnected electrically with the end conducting loop terminated in amovably supported contact member, and a second contact-membercooperating therewith, the magnetic reactions of the current in saidloop acting to force said movably supported contact member against saidother contact member.

6. In an electric switch, a contact member, a conducting member, and asecond contact member extended generally parallel and lying close tosaid`conducting member and having a connection at one end therewith bywhich said contact member is movable toward and away from saidconducting member, the magnetic reactions of the current traversing saidmovable contact member and conducting member being in a direction tourge said movable contact member toward said other Contact member.

7. In an electric switch, a rigid conducting member, a contact memberoverlying and disposed close to said conducting member and having aflexible connection at one end therewith by which current ltraversessaid contact and conducting members in opposite directions, and a secondcontact member cooperating With said first contact member.

8. Inan electric switch a contact member, a cooperating contact memberdisposed beneath said first contact member having an angularly-extendedconducting .and supporting arm, and a conducting member disposed beneathand close to and generall parallel with the angularly extended arm osaid contact member and having an electrical connection therewith at theend of said arm opposite said contact member.

9. In an electric switch a contact member, a cooperating contact memberdisposed beneath said first contact member, and a conducting memberdisposed beneath and close to and generally parallel with said contactmember and having a connection at the end of said contact member andforming a magnetic loop therewith, and a spring urging said secondcontact member towards said first contact member.

10. In an electric switch a contact member, a cooperating contact memberdisposed beneath .said first contact member, and a conducting memberdisposed beneath and close to and generally parallel with said secondcontact member and having a connection at the end of said Contact memberand formino` a magnetic loop therewith, and an insulated spring bearingagainst said conducting member and said second Contact member.

11. In an electric switch, a movable contact member, means providing acurrent path on opposite sides of and close to said contact member, anda cooperating contact member disposed in position to be engaged forciblyby said movable contact member due to the current reactions between itand said conducting path.

12. In an electric switch a movable contact member, means overlying andclose to and in series with said contact member providing a current pathin the same direction as in said contact member, and a cooperatingcontact member disposed in position Vto be pressed against by saidmovable contact member due to the magnetic reactions between it and saidcurrent path.

13. In an electric switch, a conducting member having closely spacedupper and lower parallel conducting sections through which current isadapted to pass in opposite directions, and a movable contact mem'.-ber(extended in the length of and disposed between said conductingsections and adapted to be traversed by current in a path generallyparallel to said sections.

14. In an electric switch, a. rigid conducting member having upper andlower closely spaced parallel sections connected at their outer ends, acontact member disposed between and extended in the direction of thelength of said upper and lower section and having a iexible connectionwith the inner end of said lower section.

15. In an electric switch, a contact structure comprising a rigidconducting support having upper and lower parallel and closely spacedconducting sections connected at their outer ends, an arcing memberextended through .said support between said sections and in thedirection of the length thereof, and having an electrical connectiontherewith at the inner end\of said lower horizontal section.

16. In an electric switch, a rigid conducting support having upper andlower closely spaced parallel conducting sections having a connection attheir outer ends, saidlower section having an up-standing lower end, a

contact member extended freely through said f connection and insulatedtherefrom and extended into the space between said upper and lowersections and having a flexible connection with said upturned inner end,and an insulating spring carried by said lower secion and bearingagainst said contact mem- 17. In an electric switch, a rigid conductingsupport having upper and lower closely spaced parallel conductingsections having a connection at their outer ends and an opening in saidconnection, a contact member passed freely through said opening into thespace between said sections and extended in the direction of the lengththereof, and an insulating sleeve surrounding said contact memberin-said opening, the inner end of said lower conducting section beingupstanding and the inner end of said contact member having a pivotalconnection therewith.

18. In an electric switch, a conducting support having upper` and lowerclosely spaced parallel conducting sections having a connection at theirouter ends with an opening in said connection, a contact member passedfreely through said opening into the space between said sections andextended `in the direction of the length thereof, an insulating sleevesurrounding said contact member in said opening, the inner end of saidlower conducting section being upstanding and the inner end of saidcontact member having a pivotal connection therewith, and a compressionspring carried by said lower section bearing against said insulatingsleeve.

19. In an electric switch, a conducting support comprising a horizontalbar reflexed to provide upper and lower closely spaced horizontalsections and an outer vertical vend connection section and an upstandinginner free end at said lower section, a contact member extended into thespace be,- tween said sections in the direction of the lengths thereofand having a ivotal connection with said upstanding en and means torestrain the free inner end of said lower section against unduedisplacement.

20. In an electric switch, a conducting support comprising a horizontalbar reflexed to provide upper and lower closely spaced horizontalsections and an outer vertical end connection section and an upstandinginner free end at said lower section, a contact member extended into thespace between said sections in the directionV of the lengths thereof andhaving a pivotal connection with said upstanding end, and afixedly-supported insulated bar disposed below said contact member and'above said lower section at the free end thereof.

21. In an electricswitch, a movable switch member comprising a liftingrod, a horizontal conducting member carried by said rod at the bottomthereof, a supporting frame comprising an inverted channel membercarried by said rod beneath said conducting member, a conducting supportcomprising a horizontal bar fixed in the channel of saidvchannel memberand having oppositely extended ends providing upper and lower horizontalclosely spaced sections connected at their outer ends, the inner ends ofsaid lower sections being free, and arcing members disposed beyond theends of saidy conducting support and extended into the space betweensaid upper and lower sections and along the lengths thereof and havinglexible connections with thefree inner ends of said lower section.

22. In an electric switch, a movable switch linember comprising alifting rod, a horizontal conducting member carried by said rod at thebottom thereof, a supporting frame comprising an inverted channel membercarried b f ysaid rod beneatl1.said Conducting member, a horizontaleonductiner bar lixcd in the channel of said channe member and havingoppositely extended endsy providing upper and lower horizontal closelysiaced sections connected at their 'outer en s, the inner ends of saidlower sections being free, and contact members disposed beyond the endsof saidconducting sup )ort and extended into the space between `salupper and lower sections and along the tact member, a movable ctntaetmember cooperating therewith, and a solenoid having relatively movableconducting elements connected with said movable contact member disposedto react magnetically by the current `traversing them in a direction tourge said movable contact member against said stationary contact member.

In testimony whereof, I have signed my name to this specification.

CHESTER D. AINSWORTH.

in the channel of lsaid channel member and y having oppositely extendedends rovidin upper 'and lower horizontal close y space sectionsconnected at their outer ends, the inner ends of said lower sectionsbeing free and upstanding, and outstanding ,contact members locatedbeyond theends of said conducting support and extended into the` spacebetween said upper and lower sec l' tions and having ivotal connectionsat their inner endswith t e upstanding ends of said lower sections, andinsulated pins carried by and extended between the webs of saidchannelmember and over the free ends of said lower sections and under the innerends,

of said contact members. .y

24. In an electric switch, a movable switch `member comprising a liftingrod, a main bridging member com )rising an invertedl channel membercarrie loosely on said rod at its lower end, and a supporting frame forthe auxiliary contact members comprising an inverted channel memberdisposed within and laterally spaced from the webs of the aforesaidchannel member and fixed to said lifting rod and having laterallyextended frame-spacing, projections which are disposed close to theinner faces of the webs of said main bridging member.

25. In an electric switch, a stationary con-

